One basic form for a smoking article is a rod of smokable material enclosed in a combustible wrapper. Examples include cigarettes, cigarillos, and cigars, among others. The rod is preferably of uniform cross-sectional shape and dimensions throughout the length of the rod to facilitate commercial production.
Many smoking articles, particularly those which are pre-formed and provided to a consumer ready-to-use, incorporate a cylindrical filter element aligned in an end-to-end relationship with the rod of smokable material. Conventional materials for filter elements include fibrous cellulose acetate, polypropylene, polyethylene, and gathered paper material. Multiple filter elements may be utilised. The pressure drop and/or mechanical filtration efficiency of the filter or filter sections can be selected to achieve the desired smoking mechanics and filtration characteristics as may be required with the specific product design desired.
Filters are typically wrapped in plug wrap, and wrapped filters are joined to tobacco rods often through the application of tipping paper. The filter, plug wrap, and/or tipping paper may be provided with holes, preferably holes which extend through at least the tipping paper and plug wrap to provide ventilation. The size, placement, and amount of ventilation holes as well as how they can be formed are known in the art.
The wrapper enclosing the smoking article typically comprises at least a fibrous element; conventional wrappers are papers. The wrapper may have a basis weight in the range of 14-50 g/m2. The wrapper may comprise additives such as burn additives and ash improvers. Examples include sodium citrate, potassium citrate, sodium salts, potassium salts, mono-ammonium phosphate, di-sodium hydrogen phosphate, disodium hydrogen orthophosphate, sodium carbonate, diammonium phosphate.
The wrapper may comprise fillers, such as calcium carbonate, mica, perlite, clays, alumina, magnesium oxide, and titanium oxide or further additives such as starch, alginate, and methylcellulose.
The wrapper may be partially or entirely non-paper, such as the wrappers described in International Patent Applications, Publications Nos. WO 96/07336 and WO 01/41590. Such wrappers assist in the reduction of sidestream smoke components, but still provide a smoking article which has similar burning and ashing characteristics to conventional products.
The smokable material may be any combustible material which provides smoke, such as cut tobacco or other smokable filler material.
Where inorganic filler material is used it might be one or more of perlite, alumina, diatomaceous earth, calcium carbonate, vermiculite, magnesium oxide, magnesium sulphate, zinc oxide, calcium sulphate, pumice, titanium dioxide, calcium aluminate or other insoluble aluminates, or other inorganic filler materials. The density range of the materials might be in the range of 0.1-5.7 g/cm3. An inorganic filler material having a low density, for example less than 3 g/cm3, may improve ash characteristics of the product by reducing the density of the product.
The smokable material may comprise an aerosol generating means which could include polyhydric alcohols, such as glycerol, propylene glycol and triethylene glycol; esters, such as triethyl citrate or triacetin, high boiling point hydrocarbons, or non-polyols, such as glycols, sorbitol or lactic acid. Furthermore, binders may be used, which can include alginic binders such as ammonium alginate, sodium alginate, sodium calcium alginate, calcium ammonium alginate, potassium alginate, magnesium alginate, triethanol-amine alginate and propylene glycol alginate as well as organic binders such as cellulose, sodium carboxymethylcellulose, methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose ethers, gum arabic, gum ghatti, gum tragacanth, Karaya, locust bean, acacia, guar, quince seed, xanthan gums, agar, agarose, carrageenans, furoidan, furcellaran, and starch.
The smoking article may comprise one or more flavouring agents such as tobacco extract flavours, menthol, vanillin or cocoa.
There are a number of ways to improve the appearance of smoking articles or distinguish one type or source of smoking articles from another. For example, cigar appearance can be improved where artificial tobacco sheets are used as cigar wrappers by embossing or printing a leaf pattern on the wrapper so that they more closely resemble natural tobacco. An example of distinguishing types of smoking articles is to provide an indicator on individual smoking articles, such as printing the name or trademark of the article on the wrapping.
Despite these methods, there remains a need in the art for novel, innovative ways to improve the appearance of smoking articles or distinguish smoking articles.